I'm not sure how old the guns you're referring to are, but until relatively recently, having a gun loaded and ready to fire was a very involved process. Most firearms used in the US Civil War, such as the 1841 Springfield had an external hammer, which needed to be manually pulled back, with powder then placed in the pan it was covering and down the muzzle.

There's little to no danger for the gun firing, because you have no propellant and no means to ignite any residue of the propellant leftover from previous firings, so a misfire is unlikely.

Related question: When did trigger discipline enter "common" training, as in when did everyone (civilians included) start caring about it?